Any control interface is by definition acting on something dynamic, so even pushing a physical button, we expect the some status to reflect the result instantly.

I think touchscreen could be best used as a step above joysticks, when an action cannot just be summed by a on/off (or +/-) state, or a vector in one direction.

Imagine in a military setting if you need to open a communication channel with 4 teams moving close to each other to warn them of a nearby enemy. Would you prefer to switch the “open communication” lever, check the team numbers, push the buttons 1, 5, 6, 12 and the “open channel” button. Or circle them directly on the map and click “open communication” on the right side panel?

I also think that a lot of touchscreen interface are immature and ill thought, but it would be the same issue with stupid buttons like we can find in so many cars for instance (why would the parking brake switch be next to the A/C on/off ?)

I think you just talked me into making some sort of huge steampunk button controller for slack... Have a label with the contact name, an incandescent lamp for new message status then a button to chose that to go to the conversation... Hmmm now all I need to find is some time